THE mechanical response and deformation mechanisms of pure nickel under nanoindentation were systematically investigated using molecular dynamics(MD)simulations,with a particular focus on the novel interplay between c...THE mechanical response and deformation mechanisms of pure nickel under nanoindentation were systematically investigated using molecular dynamics(MD)simulations,with a particular focus on the novel interplay between crystallographic orientation,grain boundary(GB)proximity,and pore characteristics(size/location).This study compares single-crystal nickel models along[100],[110],and[111]orientations with equiaxed polycrystalline models containing 0,1,and 2.5 nm pores in surface and subsurface configurations.Our results reveal that crystallographic anisotropy manifests as a 24.4%higher elastic modulus and 22.2%greater hardness in[111]-oriented single crystals compared to[100].Pore-GB synergistic effects are found to dominate the deformation behavior:2.5 nm subsurface pores reduce hardness by 25.2%through stress concentration and dislocation annihilation at GBs,whereas surface pores enable mechanical recovery via accelerated dislocation generation post-collapse.Additionally,size-dependent deformation regimes were identified,with 1 nm pores inducing negligible perturbation due to rapid atomic rearrangement,in contrast with persistent softening in 2.5 nm pores.These findings establish atomic-scale design principles for defect engineering in nickel-based aerospace components,demonstrating how crystallographic orientation,pore configuration,and GB interactions collectively govern nanoindentation behavior.展开更多
Photo-assisted lithium–sulfur batteries(PALSBs)offer an eco-friendly solution to address the issue of sluggish reaction kinetics of conventional LSBs.However,designing an efficient photoelectrode for practical implem...Photo-assisted lithium–sulfur batteries(PALSBs)offer an eco-friendly solution to address the issue of sluggish reaction kinetics of conventional LSBs.However,designing an efficient photoelectrode for practical implementation remains a significant challenge.Herein,we construct a free-standing polymer–inorganic hybrid photoelectrode with a direct Z-scheme heterostructure to develop high-efficiency PALSBs.Specifically,polypyrrole(PPy)is in situ vapor-phase polymerized on the surface of N-doped TiO_(2) nanorods supported on carbon cloth(N-TiO_(2)/CC),thereby forming a well-defined p–n heterojunction.This architecture efficiently facilitates the carrier separation of photo-generated electron–hole pairs and significantly enhances carrier transport by creating a built-in electric field.Thus,the PPy@N-TiO_(2)/CC can simultaneously act as a photocatalyst and an electrocatalyst to accelerate the reduction and evolution of sulfur,enabling ultrafast sulfur redox dynamics,as convincingly validated by both theoretical simulations and experimental results.Consequently,the PPy@N-TiO_(2)/CC PALSB achieves a high discharge capacity of 1653 mAh g−1,reaching 98.7%of the theoretical value.Furthermore,5 h of photo-charging without external voltage enables the PALSB to deliver a discharge capacity of 333 mAh g−1,achieving dual-mode energy harvesting capabilities.This work successfully integrates solar energy conversion and storage within a rechargeable battery system,providing a promising strategy for sustainable energy storage technologies.展开更多
Mitochondrial dysfunction has emerged as a critical factor in the etiology of various neurodevelopmental disorders, including autism spectrum disorders, attention-deficit/hyperactivity disorder, and Rett syndrome. Alt...Mitochondrial dysfunction has emerged as a critical factor in the etiology of various neurodevelopmental disorders, including autism spectrum disorders, attention-deficit/hyperactivity disorder, and Rett syndrome. Although these conditions differ in clinical presentation, they share fundamental pathological features that may stem from abnormal mitochondrial dynamics and impaired autophagic clearance, which contribute to redox imbalance and oxidative stress in neurons. This review aimed to elucidate the relationship between mitochondrial dynamics dysfunction and neurodevelopmental disorders. Mitochondria are highly dynamic organelles that undergo continuous fusion and fission to meet the substantial energy demands of neural cells. Dysregulation of these processes, as observed in certain neurodevelopmental disorders, causes accumulation of damaged mitochondria, exacerbating oxidative damage and impairing neuronal function. The phosphatase and tensin homolog-induced putative kinase 1/E3 ubiquitin-protein ligase pathway is crucial for mitophagy, the process of selectively removing malfunctioning mitochondria. Mutations in genes encoding mitochondrial fusion proteins have been identified in autism spectrum disorders, linking disruptions in the fusion-fission equilibrium to neurodevelopmental impairments. Additionally, animal models of Rett syndrome have shown pronounced defects in mitophagy, reinforcing the notion that mitochondrial quality control is indispensable for neuronal health. Clinical studies have highlighted the importance of mitochondrial disturbances in neurodevelopmental disorders. In autism spectrum disorders, elevated oxidative stress markers and mitochondrial DNA deletions indicate compromised mitochondrial function. Attention-deficit/hyperactivity disorder has also been associated with cognitive deficits linked to mitochondrial dysfunction and oxidative stress. Moreover, induced pluripotent stem cell models derived from patients with Rett syndrome have shown impaired mitochondrial dynamics and heightened vulnerability to oxidative injury, suggesting the role of defective mitochondrial homeostasis in these disorders. From a translational standpoint, multiple therapeutic approaches targeting mitochondrial pathways show promise. Interventions aimed at preserving normal fusion-fission cycles or enhancing mitophagy can reduce oxidative damage by limiting the accumulation of defective mitochondria. Pharmacological modulation of mitochondrial permeability and upregulation of peroxisome proliferator-activated receptor gamma coactivator 1-alpha, an essential regulator of mitochondrial biogenesis, may also ameliorate cellular energy deficits. Identifying early biomarkers of mitochondrial impairment is crucial for precision medicine, since it can help clinicians tailor interventions to individual patient profiles and improve prognoses. Furthermore, integrating mitochondria-focused strategies with established therapies, such as antioxidants or behavioral interventions, may enhance treatment efficacy and yield better clinical outcomes. Leveraging these pathways could open avenues for regenerative strategies, given the influence of mitochondria on neuronal repair and plasticity. In conclusion, this review indicates mitochondrial homeostasis as a unifying therapeutic axis within neurodevelopmental pathophysiology. Disruptions in mitochondrial dynamics and autophagic clearance converge on oxidative stress, and researchers should prioritize validating these interventions in clinical settings to advance precision medicine and enhance outcomes for individuals affected by neurodevelopmental disorders.展开更多
Compared to the well-studied two-dimensional(2D)ferroelectricity,the appearance of 2D antiferroelectricity is much rarer,where local dipoles from the nonequivalent sublattices within 2D monolayers are oppositely orien...Compared to the well-studied two-dimensional(2D)ferroelectricity,the appearance of 2D antiferroelectricity is much rarer,where local dipoles from the nonequivalent sublattices within 2D monolayers are oppositely oriented.Using NbOCl_(2) monolayer with competing ferroelectric(FE)and antiferroelectric(AFE)phases as a 2D material platform,we demonstrate the emergence of intrinsic antiferroelectricity in NbOCl_(2) monolayer under experimentally accessible shear strain,along with new functionality associated with electric field-induced AFE-to-FE phase transition.Specifically,the complex configuration space accommodating FE and AFE phases,polarization switching kinetics,and finite temperature thermodynamic properties of 2D NbOCl_(2) are all accurately predicted by large-scale molecular dynamics simulations based on deep learning interatomic potential model.Moreover,room temperature stable antiferroelectricity with low polarization switching barrier and one-dimensional collinear polarization arrangement is predicted in shear-deformed NbOCl_(2) monolayer.The transition from AFE to FE phase in 2D NbOCl_(2) can be triggered by a low critical electric field,leading to a double polarization–electric(P–E)loop with small hysteresis.A new type of optoelectronic device composed of AFE-NbOCl_(2) is proposed,enabling electric“writing”and nonlinear optical“reading”logical operation with fast operation speed and low power consumption.展开更多
Mesenchymal stem cells(MSCs),which are mechanosensitive cells,mediate the cells crosstalk in response to mechanical force,thereby playing a crucial role in bone homeostasis.Migrasomes serve as an important mediator fo...Mesenchymal stem cells(MSCs),which are mechanosensitive cells,mediate the cells crosstalk in response to mechanical force,thereby playing a crucial role in bone homeostasis.Migrasomes serve as an important mediator for cellular communication.However,whether the mechanical stimulus regulates the biology and property of migrasomes on bone metabolism remains unknown.This study shows that mechanical stimulus could promote MSCs to synthesize and secrete migrasomes,which could significantly alleviate chronic infectious bone destruction in periodontal tissue by inhibiting osteoclastic differentiation of macrophage and reestablishing local immune microenvironment.Mechanistically,miR-29b-3p is more abundant in migrasomes from mechanical force stimulated MSCs than in control ones.MiR-29b-3p blocks the activation of pyrin domain containing protein 3(NLRP3)and mitochondrial DNA(mtDNA)release by directly targeting on Tet1.Thus,mechanical sensing migrasomes inhibit osteoclast differentiation to alleviate inflammation induced bone destruction.These findings reveal that the mechanical stimulus controls the formation and properties of migrasomes,which provides a new biotechnological strategy for chronic infectious bone destruction intervention.展开更多
We investigate the carrier, phonon, and spin dynamics in the ferromagnetic semiconductor(In,Fe)Sb using ultrafast optical pump-probe spectroscopy. We discover two anomalies near T^(*)(~40 K) and T^(†)(~200 K) in the p...We investigate the carrier, phonon, and spin dynamics in the ferromagnetic semiconductor(In,Fe)Sb using ultrafast optical pump-probe spectroscopy. We discover two anomalies near T^(*)(~40 K) and T^(†)(~200 K) in the photoexcited carrier dynamics, which can be attributed to the electron-spin and spin-lattice scattering processes influenced by the magnetic phase transition and modifications in magnetic anisotropy. The magnetization change can be revealed by the dynamics of coherent acoustic phonon. We also observe abrupt changes in the photoinduced spin dynamics near T^(*)and T^(†), which not only illustrate the spin-related scatterings closely related to the long-range magnetic order, but also reveal the D'yakonov–Perel and Elliott–Yafet mechanisms dominating at temperatures below and above T^(†), respectively. Our findings provide important insights into the nonequilibrium properties of the photoexcited(In,Fe)Sb.展开更多
The conventional Kibble–Zurek mechanism,describing driven dynamics across critical points based on the adiabatic-impulse scenario(AIS),has attracted broad attention.However,the driven dynamics at the tricritical poin...The conventional Kibble–Zurek mechanism,describing driven dynamics across critical points based on the adiabatic-impulse scenario(AIS),has attracted broad attention.However,the driven dynamics at the tricritical point with two independent relevant directions have not been adequately studied.Here,we employ the time-dependent variational principle to study the driven critical dynamics at a one-dimensional supersymmetric Ising tricritical point.For the relevant direction along the Ising critical line,the AIS apparently breaks down.Nevertheless,we find that the critical dynamics can still be described by finite-time scaling in which the driving rate has a dimension of r_(μ)=z+1/v_(μ)with z and v_(μ)being the dynamic exponent and correlation length exponent in this direction,respectively.For driven dynamics along another direction,the driving rate has a dimension of r_(p)=z+1/v_(p)with v_(p)being another correlation length exponent.Our work brings a new fundamental perspective into nonequilibrium critical dynamics near the tricritical point,which could be realized in programmable quantum processors in Rydberg atomic systems.展开更多
The integration of renewable energy sources(RESs)with inverter interfaces has fundamentally reshaped power system dynamics,challenging traditional stability analysis frameworks designed for synchronous generator-domin...The integration of renewable energy sources(RESs)with inverter interfaces has fundamentally reshaped power system dynamics,challenging traditional stability analysis frameworks designed for synchronous generator-dominated grids.Conventional classifica-tions,which decouple voltage,frequency,and rotor angle stability,fail to address the emerging strong voltage‒angle coupling effects caused by RES dynamics.This coupling introduces complex oscillation modes and undermines system robustness,neces-sitating novel stability assessment tools.Recent studies focus on eigenvalue distributions and damping redistribution but lack quantitative criteria and interpretative clarity for coupled stability.This work proposes a transient energy-based framework to resolve these gaps.By decomposing transient energy into subsystem-dissipated components and coupling-induced energy exchange,the method establishes stability criteria compatible with a broad variety of inverter-interfaced devices while offering an intuitive energy-based interpretation for engineers.The coupling strength is also quantified by defining the relative coupling strength index,which is directly related to the transient energy interpretation of the coupled stability.Angle‒voltage coupling may induce instability by injecting transient energy into the system,even if the individual phase angle and voltage dynamics themselves are stable.The main contributions include a systematic stability evaluation framework and an energy decomposition approach that bridges theoretical analysis with practical applicability,addressing the urgent need for tools for managing modern power system evolving stability challenges.展开更多
The authors regret to report the following error made in“Spatiotemporal dynamics of neuron differentiation and migration in the developing human spinal cord;52(2025)-101283-1295;Doi:https://doi.org/10.1016/j.jgg.2025...The authors regret to report the following error made in“Spatiotemporal dynamics of neuron differentiation and migration in the developing human spinal cord;52(2025)-101283-1295;Doi:https://doi.org/10.1016/j.jgg.2025.08.004”.In Tables S1 and S2 in the supplementary materials of this paper,some items were written in Chinese.The corresponding pictures and tables were not uploaded in time.展开更多
When a perpendicular magnetic field penetrates a thin slab of a type-Ⅱ superconductor it produces vortices,with one vortex per flux quantum,h/2e.The vortices interact repulsively and form an ordered array(Abrikosov l...When a perpendicular magnetic field penetrates a thin slab of a type-Ⅱ superconductor it produces vortices,with one vortex per flux quantum,h/2e.The vortices interact repulsively and form an ordered array(Abrikosov lattice)in clean systems,while strong disorder changes the lattice into a vortex glass.The collective vortex dynamics is extremely vulnerable to external perturbations.Consequently,although of great importance,experimental observation is limited.Here we investigate type-Ⅱ superconducting films(PdBi_(2)and NbSe_(2))with surface acoustic waves(SAWs)at mK temperature.When sweeping the magnetic field at an extremely slow rate,we observe a series of spikes in the attenuation and velocity of the SAW,on average separated in field by approximately Hc1.We propose the following scenario:The vortex-free region at the edges of the film produces an edge barrier across which the vortices can enter or leave.When the applied field changes,the induced supercurrents flowing along this edge region lowers this barrier until there is an instability.At that point,vortices avalanche into(or out of)the bulk and change the vortex crystal,suggested by the sharp jump in each such spike.The vortices then gradually relax to a new stable pinned configuration,leading to a~30 s relaxation after the jump.Our observation enriches the limited experimental evidence on the important topic of real-time vortex dynamics in superconductors.展开更多
Ring polymers are ubiquitous in various fields including biomaterials,drug release and gene therapy.All of these applications involve the dynamics and diffusion process of ring polymers in a confined environment.By us...Ring polymers are ubiquitous in various fields including biomaterials,drug release and gene therapy.All of these applications involve the dynamics and diffusion process of ring polymers in a confined environment.By using dynamic light scattering(DLS),we discovered a dynamical transition for charged ring polymers with increasing ring concentration in the gel matrix from a diffusive state to a non-diffusive topological frustrated state with a more compact conformation.When the ring polymer size is smaller than the mesh size of the gel matrix,the rings are diffusive at low concentration of 5 g/L.The ring diffusion coefficient in the gel matrix is an order of magnitude smaller than that of rings in solution,obeying the Ogston's model.At high ring concentration of 40 g/L,the collective dynamical behavior of the charged rings exhibits a topologically frustrated non-diffusive state,which may originate from the inter-ring threading with the external confinement from the gel matrix.Based on our previous theoretical work,we also conjectured that in such a non-diffusive state,the ring polymers might adopt a more compact conformation with the overall size exponentν=1/3.展开更多
Surface states are expected to play a key role in broadband terahertz(THz) emitters, where photoexcited carrier distributions are confined within about 1 μm of the surface. Optical pump and THz probe spectroscopy was...Surface states are expected to play a key role in broadband terahertz(THz) emitters, where photoexcited carrier distributions are confined within about 1 μm of the surface. Optical pump and THz probe spectroscopy was used to study the dynamics of nonequilibrium charge carriers in both textured and non-textured GaAs substrates.Our findings show that the textured surface acts as an antireflective layer, greatly boosting the infrared pump laser's coupling efficiency into the semi-insulating GaAs substrate. Additionally, texturing introduces a trapassisted recombination pathway, speeding up carrier relaxation and thus reducing Joule heating. Under the same pumping and bias field conditions, the coarse-textured GaAs photoconductive antenna shows nearly 7.85 times stronger THz emission amplitude than the non-textured device, along with improvement in signal-to-noise ratio.At a fixed bias field, higher pump power increases photogenerated carrier density, causing bias field screening and subsequent saturation of THz emission. At fixed pump power, when the bias field reaches ~2.5 kV/cm, both THz emission and photocurrent spectra show a clear kink, signaling intervalley scattering from the Γ valley to the L(X) valleys under high electric fields.展开更多
Chassis-by-wire technology has gained significant attention,with the scope of chassis domain control expanding from traditional two-dimensional plane motion control to encompass three-dimensional space motion control....Chassis-by-wire technology has gained significant attention,with the scope of chassis domain control expanding from traditional two-dimensional plane motion control to encompass three-dimensional space motion control.Modern chassis-by-wire systems manage an increasing number of heterogeneous chassis execution systems,including distributed drive,all-wheel drive(AWD),brake-by-wire(BBW),steer-by-wire(SBW),rear-wheel steering(RWS),active stabilizer bar(ASB)and active suspension system(ASS),greatly enhancing the controllable degrees of freedom compared to conventional chassis configurations.To advance research in chassis domain control,it is essential to understand how these heterogeneous execution systems influence vehicle dynamics.This paper focuses on the modeling and analysis of the lateral,longitudinal,and vertical chassis control and execution systems,-as well as their impact on vehicle lateral motion.Using a vehicle simulation platform,both the vehicle dynamics model and the individual dynamics models of each execution system were developed to analyze the influence of these systems on lateral dynamics.Additionally,a hierarchical control architecture was designed to control the vehicle’s lateral stability.The effectiveness of the proposed control scheme was demonstrated and validated through hardware-in-the-loop(HIL)tests and real-world vehicle testing.展开更多
Sparse identification of nonlinear dynamics(SINDy)has made significant progress in data-driven dynamics modeling.However,determining appropriate hyperparameters and addressing the time-consuming symbolic regression pr...Sparse identification of nonlinear dynamics(SINDy)has made significant progress in data-driven dynamics modeling.However,determining appropriate hyperparameters and addressing the time-consuming symbolic regression process remain substantial challenges.This study proposes the adaptive backward stepwise selection of fast SINDy(ABSS-FSINDy),which integrates statistical learning-based estimation and technical advancements to significantly reduce simulation time.This approach not only provides insights into the conditions under which SINDy performs optimally but also highlights potential failure points,particularly in the context of backward stepwise selection(BSS).By decoding predefined features into textual expressions,ABSS-FSINDy significantly reduces the simulation time compared with conventional symbolic regression methods.We validate the proposed method through a series of numerical experiments involving both planar/spatial dynamics and high-dimensional chaotic systems,including Lotka-Volterra,hyperchaotic Rossler,coupled Lorenz,and Lorenz 96 benchmark systems.The experimental results demonstrate that ABSS-FSINDy autonomously determines optimal hyperparameters within the SINDy framework,overcoming the curse of dimensionality in high-dimensional simulations.This improvement is substantial across both lowand high-dimensional systems,yielding efficiency gains of one to three orders of magnitude.For instance,in a 20D dynamical system,the simulation time is reduced from 107.63 s to just 0.093 s,resulting in a 3-order-of-magnitude improvement in simulation efficiency.This advancement broadens the applicability of SINDy for the identification and reconstruction of high-dimensional dynamical systems.展开更多
With a three-dimensional semiclassical ensemble method, we theoretically investigated the nonsequential double ionization of Ar driven by the spatially inhomogeneous few-cycle negatively chirped laser pulses. Our resu...With a three-dimensional semiclassical ensemble method, we theoretically investigated the nonsequential double ionization of Ar driven by the spatially inhomogeneous few-cycle negatively chirped laser pulses. Our results show that the recollision time window can be precisely controlled within an isolated time interval of several hundred attoseconds, which is useful for understanding the subcycle correlated electron dynamics. More interestingly, the correlated electron momentum distribution (CEMD) exhibits a strong dependence on laser intensity. That is, at lower laser intensity, CEMD is located in the first quadrant. As the laser intensity increases,CEMD shifts almost completely to the second and fourth quadrants, and then gradually to the third quadrant.The underlying physics governing the CEMD's dependence on laser intensity is explained.展开更多
Molecular dynamics simulations were performed to investigate the sliding dynamics of a small charged ring chain along rigid cyclic diblock polyelectrolyte in catenane immersed in salt solution.We found that both the m...Molecular dynamics simulations were performed to investigate the sliding dynamics of a small charged ring chain along rigid cyclic diblock polyelectrolyte in catenane immersed in salt solution.We found that both the mean-square displacement g_(3)(t)and diffusion coefficient D of ring are influenced by the salt type,electrostatic interaction strength A and salt concentration cs.D first decreases and then increases as A increases when Ais not large.At large A,D decreases with an increase in A owing to the polyelectrolyte charge reversal caused by the aggregation of ions near it.Meanwhile,g_(3)(t)exhibited intermediate oscillating behavior at moderate A in monovalent cation salt solution.The sliding dynamics of ring can be attributed to the free energy landscape for diffusion.According to the potential of mean force(PMF)of ring chain,we found that our simulation results agreed well with the theoretical results of Lifson-Jackson formula.This study can provide a practical model for the diffusion of charged particles in different dielectric and periodic media,and provides a new perspective for regulating the sliding dynamics of mechanically interlocked molecules in electrolyte solutions.展开更多
Martensitic transformation plays a pivotal role in strengthening and hardening of steels,yet an accu-rate interatomic potential for a comprehensive description of the martensitic phase formation in Fe-C alloys is lack...Martensitic transformation plays a pivotal role in strengthening and hardening of steels,yet an accu-rate interatomic potential for a comprehensive description of the martensitic phase formation in Fe-C alloys is lacking.Herein,we developed a deep learning-based interatomic potential to perform molecu-lar dynamics(MD)simulations to study the martensitic phase transformation across a range of carbon(C)concentrations.The results revealed that an increased C concentration leads to a suppressed phase boundary movement and a decelerated phase transformation rate.To overcome the timescale limitations inherent in MD simulations,metadynamics sampling was employed to accelerate the simulations of C dif-fusion.We found that C atoms tend to cluster at distances equivalent to the lattice parameter of Fe with the same sublattice occupation,leading to local lattice tetragonality.Such C-ordered structures effectively inhibit dislocation movement and enhance strength.The stress field induced by dislocations facilitates a higher degree of ordering,and the formation of C-ordered structures was identified as a potentially cru-cial strengthening mechanism for martensitic steels.The consistency between our simulation results and reported experimental observations underscores the effectiveness of the developed DP model in simu-lating martensitic phase transformation in Fe-C alloys,providing detailed insights into the mechanisms underlying this process.This work not only advances the understanding of martensitic phase transforma-tions in Fe-C alloys but also establishes a powerful computational framework for designing steels with optimized mechanical properties through the precise control of carbon ordering and dislocation behavior.展开更多
We consider matter-wave solitons in spin-orbit coupled Bose-Einstein condensates embedded in an optical lattice and study the dynamics of the soliton within the framework of Gross-Pitaevskii equations.We express spin ...We consider matter-wave solitons in spin-orbit coupled Bose-Einstein condensates embedded in an optical lattice and study the dynamics of the soliton within the framework of Gross-Pitaevskii equations.We express spin components of the soliton pair in terms of nonlinear Bloch equations and investigate the effective spin dynamics.It is seen that the effective magnetic field that appears in the Bloch equation is affected by optical lattices,and thus the optical lattice influences the precessional frequency of the spin components.We make use of numerical approaches to investigate the dynamical behavior of density profiles and center-of-mass of the soliton pair in the presence of the optical lattice.It is shown that the spin density is periodically varying due to flipping of spinors between the two states.The amplitude of spin-flipping oscillation increases with lattice strength.We find that the system can also exhibit interesting nonlinear behavior for chosen values of parameters.We present a fixed point analysis to study the effects of optical lattices on the nonlinear dynamics of the spin components.It is seen that the optical lattice can act as a control parameter to change the dynamical behavior of the spin components from periodic to chaotic.展开更多
Portal vein stenosis is one of the common complications after liver transplantation in children.Accurate hemodynamic assessment is crucial for predicting the risk of complications after liver transplantation.In order ...Portal vein stenosis is one of the common complications after liver transplantation in children.Accurate hemodynamic assessment is crucial for predicting the risk of complications after liver transplantation.In order to predict the location of portal vein thrombosis after liver transplantation surgery,single-outlet and three-outlet vascular models were reconstructed from computed tomography images by commercial software MIMICS.The velocity field was measured using a 9.4 T magnetic resonance imaging scanner.Based on the experiment data of magnetic resonance velocimetry,computational fluid dynamics was verified,validated and then used to study the pressure and shear stresses on the wall of the two portal vein models.The simulation results can serve for the clinical prediction of early thrombosis after liver transplantation in portal vein.展开更多
This paper addresses urban sustainability challenges amid global urbanization, emphasizing the need for innova tive approaches aligned with the Sustainable Development Goals. While traditional tools and linear models ...This paper addresses urban sustainability challenges amid global urbanization, emphasizing the need for innova tive approaches aligned with the Sustainable Development Goals. While traditional tools and linear models offer insights, they fall short in presenting a holistic view of complex urban challenges. System dynamics (SD) models that are often utilized to provide holistic, systematic understanding of a research subject, like the urban system, emerge as valuable tools, but data scarcity and theoretical inadequacy pose challenges. The research reviews relevant papers on recent SD model applications in urban sustainability since 2018, categorizing them based on nine key indicators. Among the reviewed papers, data limitations and model assumptions were identified as ma jor challenges in applying SD models to urban sustainability. This led to exploring the transformative potential of big data analytics, a rare approach in this field as identified by this study, to enhance SD models’ empirical foundation. Integrating big data could provide data-driven calibration, potentially improving predictive accuracy and reducing reliance on simplified assumptions. The paper concludes by advocating for new approaches that reduce assumptions and promote real-time applicable models, contributing to a comprehensive understanding of urban sustainability through the synergy of big data and SD models.展开更多
基金The National Natural Science Foundation of China(Grant No.12462006)Beijing Institute of Structure and Environment Engineering Joint Innovation Fund(No.BQJJ202414).
文摘THE mechanical response and deformation mechanisms of pure nickel under nanoindentation were systematically investigated using molecular dynamics(MD)simulations,with a particular focus on the novel interplay between crystallographic orientation,grain boundary(GB)proximity,and pore characteristics(size/location).This study compares single-crystal nickel models along[100],[110],and[111]orientations with equiaxed polycrystalline models containing 0,1,and 2.5 nm pores in surface and subsurface configurations.Our results reveal that crystallographic anisotropy manifests as a 24.4%higher elastic modulus and 22.2%greater hardness in[111]-oriented single crystals compared to[100].Pore-GB synergistic effects are found to dominate the deformation behavior:2.5 nm subsurface pores reduce hardness by 25.2%through stress concentration and dislocation annihilation at GBs,whereas surface pores enable mechanical recovery via accelerated dislocation generation post-collapse.Additionally,size-dependent deformation regimes were identified,with 1 nm pores inducing negligible perturbation due to rapid atomic rearrangement,in contrast with persistent softening in 2.5 nm pores.These findings establish atomic-scale design principles for defect engineering in nickel-based aerospace components,demonstrating how crystallographic orientation,pore configuration,and GB interactions collectively govern nanoindentation behavior.
基金financial support from the National Natural Science Foundation of China(22109127)the Chinese Postdoctoral Science Foundation(2021M702666),+1 种基金he Research Fund of the State Key Laboratory of Solidification Processing(NPU),China(Grant No.2023-TS-02)financial support from the Youth Project of"Shaanxi High-level Talents Introduction Plan"and the Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education)are also sincerely appreciated.
文摘Photo-assisted lithium–sulfur batteries(PALSBs)offer an eco-friendly solution to address the issue of sluggish reaction kinetics of conventional LSBs.However,designing an efficient photoelectrode for practical implementation remains a significant challenge.Herein,we construct a free-standing polymer–inorganic hybrid photoelectrode with a direct Z-scheme heterostructure to develop high-efficiency PALSBs.Specifically,polypyrrole(PPy)is in situ vapor-phase polymerized on the surface of N-doped TiO_(2) nanorods supported on carbon cloth(N-TiO_(2)/CC),thereby forming a well-defined p–n heterojunction.This architecture efficiently facilitates the carrier separation of photo-generated electron–hole pairs and significantly enhances carrier transport by creating a built-in electric field.Thus,the PPy@N-TiO_(2)/CC can simultaneously act as a photocatalyst and an electrocatalyst to accelerate the reduction and evolution of sulfur,enabling ultrafast sulfur redox dynamics,as convincingly validated by both theoretical simulations and experimental results.Consequently,the PPy@N-TiO_(2)/CC PALSB achieves a high discharge capacity of 1653 mAh g−1,reaching 98.7%of the theoretical value.Furthermore,5 h of photo-charging without external voltage enables the PALSB to deliver a discharge capacity of 333 mAh g−1,achieving dual-mode energy harvesting capabilities.This work successfully integrates solar energy conversion and storage within a rechargeable battery system,providing a promising strategy for sustainable energy storage technologies.
文摘Mitochondrial dysfunction has emerged as a critical factor in the etiology of various neurodevelopmental disorders, including autism spectrum disorders, attention-deficit/hyperactivity disorder, and Rett syndrome. Although these conditions differ in clinical presentation, they share fundamental pathological features that may stem from abnormal mitochondrial dynamics and impaired autophagic clearance, which contribute to redox imbalance and oxidative stress in neurons. This review aimed to elucidate the relationship between mitochondrial dynamics dysfunction and neurodevelopmental disorders. Mitochondria are highly dynamic organelles that undergo continuous fusion and fission to meet the substantial energy demands of neural cells. Dysregulation of these processes, as observed in certain neurodevelopmental disorders, causes accumulation of damaged mitochondria, exacerbating oxidative damage and impairing neuronal function. The phosphatase and tensin homolog-induced putative kinase 1/E3 ubiquitin-protein ligase pathway is crucial for mitophagy, the process of selectively removing malfunctioning mitochondria. Mutations in genes encoding mitochondrial fusion proteins have been identified in autism spectrum disorders, linking disruptions in the fusion-fission equilibrium to neurodevelopmental impairments. Additionally, animal models of Rett syndrome have shown pronounced defects in mitophagy, reinforcing the notion that mitochondrial quality control is indispensable for neuronal health. Clinical studies have highlighted the importance of mitochondrial disturbances in neurodevelopmental disorders. In autism spectrum disorders, elevated oxidative stress markers and mitochondrial DNA deletions indicate compromised mitochondrial function. Attention-deficit/hyperactivity disorder has also been associated with cognitive deficits linked to mitochondrial dysfunction and oxidative stress. Moreover, induced pluripotent stem cell models derived from patients with Rett syndrome have shown impaired mitochondrial dynamics and heightened vulnerability to oxidative injury, suggesting the role of defective mitochondrial homeostasis in these disorders. From a translational standpoint, multiple therapeutic approaches targeting mitochondrial pathways show promise. Interventions aimed at preserving normal fusion-fission cycles or enhancing mitophagy can reduce oxidative damage by limiting the accumulation of defective mitochondria. Pharmacological modulation of mitochondrial permeability and upregulation of peroxisome proliferator-activated receptor gamma coactivator 1-alpha, an essential regulator of mitochondrial biogenesis, may also ameliorate cellular energy deficits. Identifying early biomarkers of mitochondrial impairment is crucial for precision medicine, since it can help clinicians tailor interventions to individual patient profiles and improve prognoses. Furthermore, integrating mitochondria-focused strategies with established therapies, such as antioxidants or behavioral interventions, may enhance treatment efficacy and yield better clinical outcomes. Leveraging these pathways could open avenues for regenerative strategies, given the influence of mitochondria on neuronal repair and plasticity. In conclusion, this review indicates mitochondrial homeostasis as a unifying therapeutic axis within neurodevelopmental pathophysiology. Disruptions in mitochondrial dynamics and autophagic clearance converge on oxidative stress, and researchers should prioritize validating these interventions in clinical settings to advance precision medicine and enhance outcomes for individuals affected by neurodevelopmental disorders.
基金supported by the National Natural Science Foundation of China (Grant No.11574244 for G.Y.G.)the XJTU Research Fund for AI Science (Grant No.2025YXYC011 for G.Y.G.)the Hong Kong Global STEM Professorship Scheme (for X.C.Z.)。
文摘Compared to the well-studied two-dimensional(2D)ferroelectricity,the appearance of 2D antiferroelectricity is much rarer,where local dipoles from the nonequivalent sublattices within 2D monolayers are oppositely oriented.Using NbOCl_(2) monolayer with competing ferroelectric(FE)and antiferroelectric(AFE)phases as a 2D material platform,we demonstrate the emergence of intrinsic antiferroelectricity in NbOCl_(2) monolayer under experimentally accessible shear strain,along with new functionality associated with electric field-induced AFE-to-FE phase transition.Specifically,the complex configuration space accommodating FE and AFE phases,polarization switching kinetics,and finite temperature thermodynamic properties of 2D NbOCl_(2) are all accurately predicted by large-scale molecular dynamics simulations based on deep learning interatomic potential model.Moreover,room temperature stable antiferroelectricity with low polarization switching barrier and one-dimensional collinear polarization arrangement is predicted in shear-deformed NbOCl_(2) monolayer.The transition from AFE to FE phase in 2D NbOCl_(2) can be triggered by a low critical electric field,leading to a double polarization–electric(P–E)loop with small hysteresis.A new type of optoelectronic device composed of AFE-NbOCl_(2) is proposed,enabling electric“writing”and nonlinear optical“reading”logical operation with fast operation speed and low power consumption.
基金supported by the National Key Research and Development Program of China(No.2022YFA1105800(R.L.Y.))Clinical Medicine Plus X-Young Scholars Project of Peking University(No.2025PKULCXQ015(R.L.Y.))+2 种基金Research Foundation of Peking University School and Hospital of Stomatology(No.PKUSS20230103)the Fundamental Research Funds for the Central Universities-Peking University Clinical Scientist Training Program(No.L232107(R.L.Y.))Beijing Municipal Natural Science Foundation-Haidian Original Innovation Joint Fund(Nos.L222001(Xiaomo Liu)and L232107(Jie Shi)).
文摘Mesenchymal stem cells(MSCs),which are mechanosensitive cells,mediate the cells crosstalk in response to mechanical force,thereby playing a crucial role in bone homeostasis.Migrasomes serve as an important mediator for cellular communication.However,whether the mechanical stimulus regulates the biology and property of migrasomes on bone metabolism remains unknown.This study shows that mechanical stimulus could promote MSCs to synthesize and secrete migrasomes,which could significantly alleviate chronic infectious bone destruction in periodontal tissue by inhibiting osteoclastic differentiation of macrophage and reestablishing local immune microenvironment.Mechanistically,miR-29b-3p is more abundant in migrasomes from mechanical force stimulated MSCs than in control ones.MiR-29b-3p blocks the activation of pyrin domain containing protein 3(NLRP3)and mitochondrial DNA(mtDNA)release by directly targeting on Tet1.Thus,mechanical sensing migrasomes inhibit osteoclast differentiation to alleviate inflammation induced bone destruction.These findings reveal that the mechanical stimulus controls the formation and properties of migrasomes,which provides a new biotechnological strategy for chronic infectious bone destruction intervention.
基金supported by the National Key R&D Program of China (Grant No. 2024YFA1408502)the National Natural Science Foundation of China (Grant Nos. 92365102, 62027807, 12474107, and 12174383)+1 种基金the Chinese Academy of Sciences project for Yong Scientists in Basic Research (Grant No. YSBR-030)the Guangdong Basic and Applied Basic Research Foundation (Grant No. 2024A1515011600)。
文摘We investigate the carrier, phonon, and spin dynamics in the ferromagnetic semiconductor(In,Fe)Sb using ultrafast optical pump-probe spectroscopy. We discover two anomalies near T^(*)(~40 K) and T^(†)(~200 K) in the photoexcited carrier dynamics, which can be attributed to the electron-spin and spin-lattice scattering processes influenced by the magnetic phase transition and modifications in magnetic anisotropy. The magnetization change can be revealed by the dynamics of coherent acoustic phonon. We also observe abrupt changes in the photoinduced spin dynamics near T^(*)and T^(†), which not only illustrate the spin-related scatterings closely related to the long-range magnetic order, but also reveal the D'yakonov–Perel and Elliott–Yafet mechanisms dominating at temperatures below and above T^(†), respectively. Our findings provide important insights into the nonequilibrium properties of the photoexcited(In,Fe)Sb.
基金supported by the National Natural Science Foundation of China(Grant Nos.12222515,12075324 for S.Yin,and 12347107,1257-4160 for Y.F.Jiang)the National Key R&D Program of China(Grant No.2022YFA1402703 for Y.F.Jiang)+1 种基金the Science and Technology Projects in Guangdong Province(Grant No.2021QN02X561 for S.Yin)the Science and Technology Projects in Guangzhou City(Grant No.2025A04J5408 for S.Yin)。
文摘The conventional Kibble–Zurek mechanism,describing driven dynamics across critical points based on the adiabatic-impulse scenario(AIS),has attracted broad attention.However,the driven dynamics at the tricritical point with two independent relevant directions have not been adequately studied.Here,we employ the time-dependent variational principle to study the driven critical dynamics at a one-dimensional supersymmetric Ising tricritical point.For the relevant direction along the Ising critical line,the AIS apparently breaks down.Nevertheless,we find that the critical dynamics can still be described by finite-time scaling in which the driving rate has a dimension of r_(μ)=z+1/v_(μ)with z and v_(μ)being the dynamic exponent and correlation length exponent in this direction,respectively.For driven dynamics along another direction,the driving rate has a dimension of r_(p)=z+1/v_(p)with v_(p)being another correlation length exponent.Our work brings a new fundamental perspective into nonequilibrium critical dynamics near the tricritical point,which could be realized in programmable quantum processors in Rydberg atomic systems.
基金supported by the Science and Technology Project of China Southern Power Grid Co.,Ltd under Grant 036000KC23090004(GDKJXM20231026).
文摘The integration of renewable energy sources(RESs)with inverter interfaces has fundamentally reshaped power system dynamics,challenging traditional stability analysis frameworks designed for synchronous generator-dominated grids.Conventional classifica-tions,which decouple voltage,frequency,and rotor angle stability,fail to address the emerging strong voltage‒angle coupling effects caused by RES dynamics.This coupling introduces complex oscillation modes and undermines system robustness,neces-sitating novel stability assessment tools.Recent studies focus on eigenvalue distributions and damping redistribution but lack quantitative criteria and interpretative clarity for coupled stability.This work proposes a transient energy-based framework to resolve these gaps.By decomposing transient energy into subsystem-dissipated components and coupling-induced energy exchange,the method establishes stability criteria compatible with a broad variety of inverter-interfaced devices while offering an intuitive energy-based interpretation for engineers.The coupling strength is also quantified by defining the relative coupling strength index,which is directly related to the transient energy interpretation of the coupled stability.Angle‒voltage coupling may induce instability by injecting transient energy into the system,even if the individual phase angle and voltage dynamics themselves are stable.The main contributions include a systematic stability evaluation framework and an energy decomposition approach that bridges theoretical analysis with practical applicability,addressing the urgent need for tools for managing modern power system evolving stability challenges.
文摘The authors regret to report the following error made in“Spatiotemporal dynamics of neuron differentiation and migration in the developing human spinal cord;52(2025)-101283-1295;Doi:https://doi.org/10.1016/j.jgg.2025.08.004”.In Tables S1 and S2 in the supplementary materials of this paper,some items were written in Chinese.The corresponding pictures and tables were not uploaded in time.
基金supported by the National Key Research Program of China(Grant Nos.2021YFA1401900,2022YFA1403300,and 2020YFA0309100)the Innovation Program for Quantum Science and Technology(Grant Nos.2021ZD0302602 and 2024ZD0300103)+1 种基金the National Natural Science Foundation of China(Grant No.12074073)for samplefabrication and measurementthe support by the The Basic Research Program of the Chinese Academy of Sciences Based on Major Scientific Infrastructures(Grant No.JZHKYPT-2021-08).
文摘When a perpendicular magnetic field penetrates a thin slab of a type-Ⅱ superconductor it produces vortices,with one vortex per flux quantum,h/2e.The vortices interact repulsively and form an ordered array(Abrikosov lattice)in clean systems,while strong disorder changes the lattice into a vortex glass.The collective vortex dynamics is extremely vulnerable to external perturbations.Consequently,although of great importance,experimental observation is limited.Here we investigate type-Ⅱ superconducting films(PdBi_(2)and NbSe_(2))with surface acoustic waves(SAWs)at mK temperature.When sweeping the magnetic field at an extremely slow rate,we observe a series of spikes in the attenuation and velocity of the SAW,on average separated in field by approximately Hc1.We propose the following scenario:The vortex-free region at the edges of the film produces an edge barrier across which the vortices can enter or leave.When the applied field changes,the induced supercurrents flowing along this edge region lowers this barrier until there is an instability.At that point,vortices avalanche into(or out of)the bulk and change the vortex crystal,suggested by the sharp jump in each such spike.The vortices then gradually relax to a new stable pinned configuration,leading to a~30 s relaxation after the jump.Our observation enriches the limited experimental evidence on the important topic of real-time vortex dynamics in superconductors.
基金supported by the National Natural Science Foundation of China(No.22273114)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB0770101)+1 种基金the National Key R&D Program of China(No.2023YFE0124500),the National Key R&D Program of China(No.2023YFC2411203)International Partnership Program of the Chinese Academy of Sciences(No.027GJHZ2022061FN)。
文摘Ring polymers are ubiquitous in various fields including biomaterials,drug release and gene therapy.All of these applications involve the dynamics and diffusion process of ring polymers in a confined environment.By using dynamic light scattering(DLS),we discovered a dynamical transition for charged ring polymers with increasing ring concentration in the gel matrix from a diffusive state to a non-diffusive topological frustrated state with a more compact conformation.When the ring polymer size is smaller than the mesh size of the gel matrix,the rings are diffusive at low concentration of 5 g/L.The ring diffusion coefficient in the gel matrix is an order of magnitude smaller than that of rings in solution,obeying the Ogston's model.At high ring concentration of 40 g/L,the collective dynamical behavior of the charged rings exhibits a topologically frustrated non-diffusive state,which may originate from the inter-ring threading with the external confinement from the gel matrix.Based on our previous theoretical work,we also conjectured that in such a non-diffusive state,the ring polymers might adopt a more compact conformation with the overall size exponentν=1/3.
基金supported by the National Key Research and Development Program of China (Grant No.2023YFF0719200)the National Natural Science Foundation of China (Grant Nos.62322115,U24A20226,62588201,62435010,and 62335012)+2 种基金the 111 Project (Grant No.D18014)the Key project supported by Science and Technology Commission Shanghai Municipality (Grant No.YDZX20193100004960)Science and Technology Commission of Shanghai Municipality (Grant Nos.22JC1400200 and 21S31907400)。
文摘Surface states are expected to play a key role in broadband terahertz(THz) emitters, where photoexcited carrier distributions are confined within about 1 μm of the surface. Optical pump and THz probe spectroscopy was used to study the dynamics of nonequilibrium charge carriers in both textured and non-textured GaAs substrates.Our findings show that the textured surface acts as an antireflective layer, greatly boosting the infrared pump laser's coupling efficiency into the semi-insulating GaAs substrate. Additionally, texturing introduces a trapassisted recombination pathway, speeding up carrier relaxation and thus reducing Joule heating. Under the same pumping and bias field conditions, the coarse-textured GaAs photoconductive antenna shows nearly 7.85 times stronger THz emission amplitude than the non-textured device, along with improvement in signal-to-noise ratio.At a fixed bias field, higher pump power increases photogenerated carrier density, causing bias field screening and subsequent saturation of THz emission. At fixed pump power, when the bias field reaches ~2.5 kV/cm, both THz emission and photocurrent spectra show a clear kink, signaling intervalley scattering from the Γ valley to the L(X) valleys under high electric fields.
基金Supported by National Nature Science Foundation of China(Grant Nos.52325212,52372394)National Key Research and Development Program of China(Grant Nos.2022YFE0117100,2021YFB2501201)+1 种基金Industry-University-Research Innovation Fund for Chinese Universities(Grand No.2024HT010)Fundamental Research Funds for the Central Universities.
文摘Chassis-by-wire technology has gained significant attention,with the scope of chassis domain control expanding from traditional two-dimensional plane motion control to encompass three-dimensional space motion control.Modern chassis-by-wire systems manage an increasing number of heterogeneous chassis execution systems,including distributed drive,all-wheel drive(AWD),brake-by-wire(BBW),steer-by-wire(SBW),rear-wheel steering(RWS),active stabilizer bar(ASB)and active suspension system(ASS),greatly enhancing the controllable degrees of freedom compared to conventional chassis configurations.To advance research in chassis domain control,it is essential to understand how these heterogeneous execution systems influence vehicle dynamics.This paper focuses on the modeling and analysis of the lateral,longitudinal,and vertical chassis control and execution systems,-as well as their impact on vehicle lateral motion.Using a vehicle simulation platform,both the vehicle dynamics model and the individual dynamics models of each execution system were developed to analyze the influence of these systems on lateral dynamics.Additionally,a hierarchical control architecture was designed to control the vehicle’s lateral stability.The effectiveness of the proposed control scheme was demonstrated and validated through hardware-in-the-loop(HIL)tests and real-world vehicle testing.
基金Project supported by the National Natural Science Foundation of China(Nos.12172291,12472357,and 12232015)the Shaanxi Province Outstanding Youth Fund Project(No.2024JC-JCQN-05)the 111 Project(No.BP0719007)。
文摘Sparse identification of nonlinear dynamics(SINDy)has made significant progress in data-driven dynamics modeling.However,determining appropriate hyperparameters and addressing the time-consuming symbolic regression process remain substantial challenges.This study proposes the adaptive backward stepwise selection of fast SINDy(ABSS-FSINDy),which integrates statistical learning-based estimation and technical advancements to significantly reduce simulation time.This approach not only provides insights into the conditions under which SINDy performs optimally but also highlights potential failure points,particularly in the context of backward stepwise selection(BSS).By decoding predefined features into textual expressions,ABSS-FSINDy significantly reduces the simulation time compared with conventional symbolic regression methods.We validate the proposed method through a series of numerical experiments involving both planar/spatial dynamics and high-dimensional chaotic systems,including Lotka-Volterra,hyperchaotic Rossler,coupled Lorenz,and Lorenz 96 benchmark systems.The experimental results demonstrate that ABSS-FSINDy autonomously determines optimal hyperparameters within the SINDy framework,overcoming the curse of dimensionality in high-dimensional simulations.This improvement is substantial across both lowand high-dimensional systems,yielding efficiency gains of one to three orders of magnitude.For instance,in a 20D dynamical system,the simulation time is reduced from 107.63 s to just 0.093 s,resulting in a 3-order-of-magnitude improvement in simulation efficiency.This advancement broadens the applicability of SINDy for the identification and reconstruction of high-dimensional dynamical systems.
基金supported by the National Natural Science Foundation of China (Grant No. 12074329)Nanhu Scholars Program for Young Scholars of Xinyang Normal University。
文摘With a three-dimensional semiclassical ensemble method, we theoretically investigated the nonsequential double ionization of Ar driven by the spatially inhomogeneous few-cycle negatively chirped laser pulses. Our results show that the recollision time window can be precisely controlled within an isolated time interval of several hundred attoseconds, which is useful for understanding the subcycle correlated electron dynamics. More interestingly, the correlated electron momentum distribution (CEMD) exhibits a strong dependence on laser intensity. That is, at lower laser intensity, CEMD is located in the first quadrant. As the laser intensity increases,CEMD shifts almost completely to the second and fourth quadrants, and then gradually to the third quadrant.The underlying physics governing the CEMD's dependence on laser intensity is explained.
基金supported by the National Natural Science Foundation of China(Nos.22173080,22403062,and22363005)the Jiangxi Provincial Natural Science Foundation(No.20202BABL203015)。
文摘Molecular dynamics simulations were performed to investigate the sliding dynamics of a small charged ring chain along rigid cyclic diblock polyelectrolyte in catenane immersed in salt solution.We found that both the mean-square displacement g_(3)(t)and diffusion coefficient D of ring are influenced by the salt type,electrostatic interaction strength A and salt concentration cs.D first decreases and then increases as A increases when Ais not large.At large A,D decreases with an increase in A owing to the polyelectrolyte charge reversal caused by the aggregation of ions near it.Meanwhile,g_(3)(t)exhibited intermediate oscillating behavior at moderate A in monovalent cation salt solution.The sliding dynamics of ring can be attributed to the free energy landscape for diffusion.According to the potential of mean force(PMF)of ring chain,we found that our simulation results agreed well with the theoretical results of Lifson-Jackson formula.This study can provide a practical model for the diffusion of charged particles in different dielectric and periodic media,and provides a new perspective for regulating the sliding dynamics of mechanically interlocked molecules in electrolyte solutions.
基金the National Key Research and Devel-opment Program of China(No.2022YFB3709000)the National Natural Science Foundation of China(Nos.52101019,52122408,52071023,52474397)+1 种基金support from the Fundamental Research Funds for the Central Universities(University of Science and Technology Beijing,No.FRF-TP-2021-04C1,and 06500135)supported by USTB MatCom of Beijing Advanced Innovation Center for Materials Genome Engineering.
文摘Martensitic transformation plays a pivotal role in strengthening and hardening of steels,yet an accu-rate interatomic potential for a comprehensive description of the martensitic phase formation in Fe-C alloys is lacking.Herein,we developed a deep learning-based interatomic potential to perform molecu-lar dynamics(MD)simulations to study the martensitic phase transformation across a range of carbon(C)concentrations.The results revealed that an increased C concentration leads to a suppressed phase boundary movement and a decelerated phase transformation rate.To overcome the timescale limitations inherent in MD simulations,metadynamics sampling was employed to accelerate the simulations of C dif-fusion.We found that C atoms tend to cluster at distances equivalent to the lattice parameter of Fe with the same sublattice occupation,leading to local lattice tetragonality.Such C-ordered structures effectively inhibit dislocation movement and enhance strength.The stress field induced by dislocations facilitates a higher degree of ordering,and the formation of C-ordered structures was identified as a potentially cru-cial strengthening mechanism for martensitic steels.The consistency between our simulation results and reported experimental observations underscores the effectiveness of the developed DP model in simu-lating martensitic phase transformation in Fe-C alloys,providing detailed insights into the mechanisms underlying this process.This work not only advances the understanding of martensitic phase transforma-tions in Fe-C alloys but also establishes a powerful computational framework for designing steels with optimized mechanical properties through the precise control of carbon ordering and dislocation behavior.
文摘We consider matter-wave solitons in spin-orbit coupled Bose-Einstein condensates embedded in an optical lattice and study the dynamics of the soliton within the framework of Gross-Pitaevskii equations.We express spin components of the soliton pair in terms of nonlinear Bloch equations and investigate the effective spin dynamics.It is seen that the effective magnetic field that appears in the Bloch equation is affected by optical lattices,and thus the optical lattice influences the precessional frequency of the spin components.We make use of numerical approaches to investigate the dynamical behavior of density profiles and center-of-mass of the soliton pair in the presence of the optical lattice.It is shown that the spin density is periodically varying due to flipping of spinors between the two states.The amplitude of spin-flipping oscillation increases with lattice strength.We find that the system can also exhibit interesting nonlinear behavior for chosen values of parameters.We present a fixed point analysis to study the effects of optical lattices on the nonlinear dynamics of the spin components.It is seen that the optical lattice can act as a control parameter to change the dynamical behavior of the spin components from periodic to chaotic.
基金the Interdisciplinary Program of Shanghai Jiao Tong University(No.YG2021QN36)the National Natural Science Foundation of China(Nos.82000615 and 52106050)the Natural Science Foundation of Shanghai(No.21ZR1431800)。
文摘Portal vein stenosis is one of the common complications after liver transplantation in children.Accurate hemodynamic assessment is crucial for predicting the risk of complications after liver transplantation.In order to predict the location of portal vein thrombosis after liver transplantation surgery,single-outlet and three-outlet vascular models were reconstructed from computed tomography images by commercial software MIMICS.The velocity field was measured using a 9.4 T magnetic resonance imaging scanner.Based on the experiment data of magnetic resonance velocimetry,computational fluid dynamics was verified,validated and then used to study the pressure and shear stresses on the wall of the two portal vein models.The simulation results can serve for the clinical prediction of early thrombosis after liver transplantation in portal vein.
基金sponsored by the U.S.Department of Housing and Urban Development(Grant No.NJLTS0027-22)The opinions expressed in this study are the authors alone,and do not represent the U.S.Depart-ment of HUD’s opinions.
文摘This paper addresses urban sustainability challenges amid global urbanization, emphasizing the need for innova tive approaches aligned with the Sustainable Development Goals. While traditional tools and linear models offer insights, they fall short in presenting a holistic view of complex urban challenges. System dynamics (SD) models that are often utilized to provide holistic, systematic understanding of a research subject, like the urban system, emerge as valuable tools, but data scarcity and theoretical inadequacy pose challenges. The research reviews relevant papers on recent SD model applications in urban sustainability since 2018, categorizing them based on nine key indicators. Among the reviewed papers, data limitations and model assumptions were identified as ma jor challenges in applying SD models to urban sustainability. This led to exploring the transformative potential of big data analytics, a rare approach in this field as identified by this study, to enhance SD models’ empirical foundation. Integrating big data could provide data-driven calibration, potentially improving predictive accuracy and reducing reliance on simplified assumptions. The paper concludes by advocating for new approaches that reduce assumptions and promote real-time applicable models, contributing to a comprehensive understanding of urban sustainability through the synergy of big data and SD models.
